NASA's Jet Propulsion Laboratory notes that the flyby, "presents a truly outstanding scientific opportunity to study the physical properties of this object," adding, "this is the closest approach by a known object this large until 1999 AN10 approaches within 1 lunar distance in August 2027. The last approach closer than this by an object with H < 20 was by 2004 XP14 in July 2006 at 1.1 lunar distances."

According to NASA, the asteroid's orbit is "extremely eccentric" and highly inclined (or tilted). And NASA's Pan-STARRS project didn't discover the object until Oct. 10, so if it were actually on an Earth-hitting path, it would have been bad news for us. NASA, for what it's worth, says it would be alarmed over an asteroid set to pass Earth by a margin of 20,000 miles or closer. But 310,000 miles? Fine.